Bash: loop over a list of (possibly non-existing) files using wildcards with nullglob (or failglob) option

Let’s say you’re working in Bash, and you want to loop over a list of files, using wildcards.

The basic code is:

#!/bin/bash
for f in /path/to/files/*; do
echo "Found file: $f"
done

Easy as that. However, there could be a problem with this code: if the wildcard does not expand to actual files (i.e. there’s no file under /path/to/files/ directory), $f will expand to the path string itself, and the for loop will still be executed one time with $f containing “/path/to/files/*”.

How to prevent this from happening? Nullglob is what you’re looking for.

Nullglob, quoting shopts man page, “allows filename patterns which match no files to expand to a null string, rather than themselves”.

Using shopt -s you can enable BASH optional behaviors, like Nullglob. Here’s the final code: